gsrsb (version 1.2.1)

initLocPeak: Find the Location of Maximum, Standard OBF and POC

Description

Calculate the location of maximal tyep I error of the standard O'Brien-Fleming and Pocock refined secondary boundaries.

Usage

initLocPeak(alpha, tVec, cvec, type = 2, initIntvl = c(1, 4))

Value

location of maximum, a number between 1 and the number of interims

Arguments

alpha

type I error.

tVec

information vector.

cvec

primary group sequential boundary.

type

type of the test procedure for the secondary endpoint. O'Brien- Fleming (OBF) type error spending funciton is 1, Pocock (POC) type error spending funciton is 2.

initIntvl

computing paramter, a pair of numbers containing the end-points of the interval to be searched for the root.

Author

Jiangtao Gou

Details

This function search the location of the maximal point, in order to calculate the standard (origiinal) O'Brien-Fleming (OBF) and Pocock (POC) refined secondary boundaries.

References

O'Brien, P. C., and Fleming, T. R. (1979). A multiple testing procedure for clinical trials. Biometrics 35, 549-556.

Pocock, S. J. (1977). Group sequential methods in the design and analysis of clinical trials. Biometrika 64, 191-199.

Tamhane, A. C., Gou, J., Jennison, C., Mehta, C. R., and Curto, T. (2018). A gatekeeping procedure to test a primary and a secondary endpoint in a group sequential design with multiple interim looks. Biometrics, to appear.

See Also

SecondaryBoundary, ldInitLocBeak

Examples

require(mvtnorm)
K <- 8
gammaVec <- sqrt((1:K)/K)
tVec <- gammaVec^2
alpha <- 0.025
c <- 2.072274
cvec <- c/gammaVec
loc <- initLocPeak(alpha,tVec,cvec,type=2,initIntvl=c(1,3))